rust-clippy/tests/ui/for_loop.stderr

error: for loop over `option`, which is an `Option`. This is more readably written as an `if let` statement.
  --> $DIR/for_loop.rs:17:14
   |
17 |     for x in option {
   |              ^^^^^^
   |
   = note: `-D for-loop-over-option` implied by `-D warnings`
   = help: consider replacing `for x in option` with `if let Some(x) = option`

error: for loop over `result`, which is a `Result`. This is more readably written as an `if let` statement.
  --> $DIR/for_loop.rs:22:14
   |
22 |     for x in result {
   |              ^^^^^^
   |
   = note: `-D for-loop-over-result` implied by `-D warnings`
   = help: consider replacing `for x in result` with `if let Ok(x) = result`

error: for loop over `option.ok_or("x not found")`, which is a `Result`. This is more readably written as an `if let` statement.
  --> $DIR/for_loop.rs:26:14
   |
26 |     for x in option.ok_or("x not found") {
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: consider replacing `for x in option.ok_or("x not found")` with `if let Ok(x) = option.ok_or("x not found")`

error: you are iterating over `Iterator::next()` which is an Option; this will compile but is probably not what you want
  --> $DIR/for_loop.rs:31:5
   |
31 | /     for x in v.iter().next() {
32 | |         println!("{}", x);
33 | |     }
   | |_____^
   |
   = note: `-D iter-next-loop` implied by `-D warnings`

error: for loop over `v.iter().next().and(Some(0))`, which is an `Option`. This is more readably written as an `if let` statement.
  --> $DIR/for_loop.rs:36:14
   |
36 |     for x in v.iter().next().and(Some(0)) {
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: consider replacing `for x in v.iter().next().and(Some(0))` with `if let Some(x) = v.iter().next().and(Some(0))`

error: for loop over `v.iter().next().ok_or("x not found")`, which is a `Result`. This is more readably written as an `if let` statement.
  --> $DIR/for_loop.rs:40:14
   |
40 |     for x in v.iter().next().ok_or("x not found") {
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: consider replacing `for x in v.iter().next().ok_or("x not found")` with `if let Ok(x) = v.iter().next().ok_or("x not found")`

error: this loop never actually loops
  --> $DIR/for_loop.rs:52:5
   |
52 | /     while let Some(x) = option {
53 | |         println!("{}", x);
54 | |         break;
55 | |     }
   | |_____^
   |
   = note: `-D never-loop` implied by `-D warnings`

error: this loop never actually loops
  --> $DIR/for_loop.rs:58:5
   |
58 | /     while let Ok(x) = result {
59 | |         println!("{}", x);
60 | |         break;
61 | |     }
   | |_____^

error: the loop variable `i` is only used to index `vec`.
  --> $DIR/for_loop.rs:84:5
   |
84 | /     for i in 0..vec.len() {
85 | |         println!("{}", vec[i]);
86 | |     }
   | |_____^
   |
   = note: `-D needless-range-loop` implied by `-D warnings`
help: consider using an iterator
   |
84 |     for <item> in &vec {
   |         ^^^^^^

error: the loop variable `i` is only used to index `vec`.
  --> $DIR/for_loop.rs:93:5
   |
93 |     for i in 0..vec.len() { let _ = vec[i]; }
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
help: consider using an iterator
   |
93 |     for <item> in &vec { let _ = vec[i]; }
   |         ^^^^^^

error: the loop variable `j` is only used to index `STATIC`.
  --> $DIR/for_loop.rs:96:5
   |
96 | /     for j in 0..4 {
97 | |         println!("{:?}", STATIC[j]);
98 | |     }
   | |_____^
   |
help: consider using an iterator
   |
96 |     for <item> in STATIC.iter().take(4) {
   |         ^^^^^^

error: the loop variable `j` is only used to index `CONST`.
   --> $DIR/for_loop.rs:100:5
    |
100 | /     for j in 0..4 {
101 | |         println!("{:?}", CONST[j]);
102 | |     }
    | |_____^
    |
help: consider using an iterator
    |
100 |     for <item> in CONST.iter().take(4) {
    |         ^^^^^^

error: the loop variable `i` is used to index `vec`
   --> $DIR/for_loop.rs:104:5
    |
104 | /     for i in 0..vec.len() {
105 | |         println!("{} {}", vec[i], i);
106 | |     }
    | |_____^
    |
help: consider using an iterator
    |
104 |     for (i, <item>) in vec.iter().enumerate() {
    |         ^^^^^^^^^^^

error: the loop variable `i` is only used to index `vec2`.
   --> $DIR/for_loop.rs:111:5
    |
111 | /     for i in 0..vec.len() {
112 | |         println!("{}", vec2[i]);
113 | |     }
    | |_____^
    |
help: consider using an iterator
    |
111 |     for <item> in vec2.iter().take(vec.len()) {
    |         ^^^^^^

error: the loop variable `i` is only used to index `vec`.
   --> $DIR/for_loop.rs:115:5
    |
115 | /     for i in 5..vec.len() {
116 | |         println!("{}", vec[i]);
117 | |     }
    | |_____^
    |
help: consider using an iterator
    |
115 |     for <item> in vec.iter().skip(5) {
    |         ^^^^^^

error: the loop variable `i` is only used to index `vec`.
   --> $DIR/for_loop.rs:119:5
    |
119 | /     for i in 0..MAX_LEN {
120 | |         println!("{}", vec[i]);
121 | |     }
    | |_____^
    |
help: consider using an iterator
    |
119 |     for <item> in vec.iter().take(MAX_LEN) {
    |         ^^^^^^

error: the loop variable `i` is only used to index `vec`.
   --> $DIR/for_loop.rs:123:5
    |
123 | /     for i in 0...MAX_LEN {
124 | |         println!("{}", vec[i]);
125 | |     }
    | |_____^
    |
help: consider using an iterator
    |
123 |     for <item> in vec.iter().take(MAX_LEN + 1) {
    |         ^^^^^^

error: the loop variable `i` is only used to index `vec`.
   --> $DIR/for_loop.rs:127:5
    |
127 | /     for i in 5..10 {
128 | |         println!("{}", vec[i]);
129 | |     }
    | |_____^
    |
help: consider using an iterator
    |
127 |     for <item> in vec.iter().take(10).skip(5) {
    |         ^^^^^^

error: the loop variable `i` is only used to index `vec`.
   --> $DIR/for_loop.rs:131:5
    |
131 | /     for i in 5...10 {
132 | |         println!("{}", vec[i]);
133 | |     }
    | |_____^
    |
help: consider using an iterator
    |
131 |     for <item> in vec.iter().take(10 + 1).skip(5) {
    |         ^^^^^^

error: the loop variable `i` is used to index `vec`
   --> $DIR/for_loop.rs:135:5
    |
135 | /     for i in 5..vec.len() {
136 | |         println!("{} {}", vec[i], i);
137 | |     }
    | |_____^
    |
help: consider using an iterator
    |
135 |     for (i, <item>) in vec.iter().enumerate().skip(5) {
    |         ^^^^^^^^^^^

error: the loop variable `i` is used to index `vec`
   --> $DIR/for_loop.rs:139:5
    |
139 | /     for i in 5..10 {
140 | |         println!("{} {}", vec[i], i);
141 | |     }
    | |_____^
    |
help: consider using an iterator
    |
139 |     for (i, <item>) in vec.iter().enumerate().take(10).skip(5) {
    |         ^^^^^^^^^^^

error: this range is empty so this for loop will never run
   --> $DIR/for_loop.rs:143:5
    |
143 | /     for i in 10..0 {
144 | |         println!("{}", i);
145 | |     }
    | |_____^
    |
    = note: `-D reverse-range-loop` implied by `-D warnings`
help: consider using the following if you are attempting to iterate over this range in reverse
    |
143 |     for i in (0..10).rev() {
    |              ^^^^^^^^^^^^^

error: this range is empty so this for loop will never run
   --> $DIR/for_loop.rs:147:5
    |
147 | /     for i in 10...0 {
148 | |         println!("{}", i);
149 | |     }
    | |_____^
    |
help: consider using the following if you are attempting to iterate over this range in reverse
    |
147 |     for i in (0...10).rev() {
    |              ^^^^^^^^^^^^^^

error: this range is empty so this for loop will never run
   --> $DIR/for_loop.rs:151:5
    |
151 | /     for i in MAX_LEN..0 {
152 | |         println!("{}", i);
153 | |     }
    | |_____^
    |
help: consider using the following if you are attempting to iterate over this range in reverse
    |
151 |     for i in (0..MAX_LEN).rev() {
    |              ^^^^^^^^^^^^^^^^^^

error: this range is empty so this for loop will never run
   --> $DIR/for_loop.rs:155:5
    |
155 | /     for i in 5..5 {
156 | |         println!("{}", i);
157 | |     }
    | |_____^

error: this range is empty so this for loop will never run
   --> $DIR/for_loop.rs:176:5
    |
176 | /     for i in 10..5+4 {
177 | |         println!("{}", i);
178 | |     }
    | |_____^
    |
help: consider using the following if you are attempting to iterate over this range in reverse
    |
176 |     for i in (5+4..10).rev() {
    |              ^^^^^^^^^^^^^^^

error: this range is empty so this for loop will never run
   --> $DIR/for_loop.rs:180:5
    |
180 | /     for i in (5+2)..(3-1) {
181 | |         println!("{}", i);
182 | |     }
    | |_____^
    |
help: consider using the following if you are attempting to iterate over this range in reverse
    |
180 |     for i in ((3-1)..(5+2)).rev() {
    |              ^^^^^^^^^^^^^^^^^^^^

error: this range is empty so this for loop will never run
   --> $DIR/for_loop.rs:184:5
    |
184 | /     for i in (5+2)..(8-1) {
185 | |         println!("{}", i);
186 | |     }
    | |_____^

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:203:15
    |
203 |     for _v in vec.iter() { }
    |               ^^^^^^^^^^ help: to write this more concisely, try: `&vec`
    |
    = note: `-D explicit-iter-loop` implied by `-D warnings`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:205:15
    |
205 |     for _v in vec.iter_mut() { }
    |               ^^^^^^^^^^^^^^ help: to write this more concisely, try: `&mut vec`

error: it is more idiomatic to loop over containers instead of using explicit iteration methods`
   --> $DIR/for_loop.rs:208:15
    |
208 |     for _v in out_vec.into_iter() { }
    |               ^^^^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `out_vec`
    |
    = note: `-D explicit-into-iter-loop` implied by `-D warnings`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:211:15
    |
211 |     for _v in array.into_iter() {}
    |               ^^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `&array`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:216:15
    |
216 |     for _v in [1, 2, 3].iter() { }
    |               ^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `&[1, 2, 3]`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:220:15
    |
220 |     for _v in [0; 32].iter() {}
    |               ^^^^^^^^^^^^^^ help: to write this more concisely, try: `&[0; 32]`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:225:15
    |
225 |     for _v in ll.iter() { }
    |               ^^^^^^^^^ help: to write this more concisely, try: `&ll`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:228:15
    |
228 |     for _v in vd.iter() { }
    |               ^^^^^^^^^ help: to write this more concisely, try: `&vd`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:231:15
    |
231 |     for _v in bh.iter() { }
    |               ^^^^^^^^^ help: to write this more concisely, try: `&bh`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:234:15
    |
234 |     for _v in hm.iter() { }
    |               ^^^^^^^^^ help: to write this more concisely, try: `&hm`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:237:15
    |
237 |     for _v in bt.iter() { }
    |               ^^^^^^^^^ help: to write this more concisely, try: `&bt`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:240:15
    |
240 |     for _v in hs.iter() { }
    |               ^^^^^^^^^ help: to write this more concisely, try: `&hs`

error: it is more idiomatic to loop over references to containers instead of using explicit iteration methods
   --> $DIR/for_loop.rs:243:15
    |
243 |     for _v in bs.iter() { }
    |               ^^^^^^^^^ help: to write this more concisely, try: `&bs`

error: you are iterating over `Iterator::next()` which is an Option; this will compile but is probably not what you want
   --> $DIR/for_loop.rs:245:5
    |
245 |     for _v in vec.iter().next() { }
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: you are collect()ing an iterator and throwing away the result. Consider using an explicit for loop to exhaust the iterator
   --> $DIR/for_loop.rs:252:5
    |
252 |     vec.iter().cloned().map(|x| out.push(x)).collect::<Vec<_>>();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D unused-collect` implied by `-D warnings`

error: the variable `_index` is used as a loop counter. Consider using `for (_index, item) in &vec.enumerate()` or similar iterators
   --> $DIR/for_loop.rs:257:5
    |
257 |     for _v in &vec { _index += 1 }
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D explicit-counter-loop` implied by `-D warnings`

error: the variable `_index` is used as a loop counter. Consider using `for (_index, item) in &vec.enumerate()` or similar iterators
   --> $DIR/for_loop.rs:261:5
    |
261 |     for _v in &vec { _index += 1 }
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: you seem to want to iterate on a map's values
   --> $DIR/for_loop.rs:321:5
    |
321 | /     for (_, v) in &m {
322 | |         let _v = v;
323 | |     }
    | |_____^
    |
    = note: `-D for-kv-map` implied by `-D warnings`
help: use the corresponding method
    |
321 |     for v in m.values() {
    |         ^

error: you seem to want to iterate on a map's values
   --> $DIR/for_loop.rs:326:5
    |
326 | /     for (_, v) in &*m {
327 | |         let _v = v;
328 | |         // Here the `*` is not actually necesarry, but the test tests that we don't suggest
329 | |         // `in *m.values()` as we used to
330 | |     }
    | |_____^
    |
help: use the corresponding method
    |
326 |     for v in (*m).values() {
    |         ^

error: you seem to want to iterate on a map's values
   --> $DIR/for_loop.rs:333:5
    |
333 | /     for (_, v) in &mut m {
334 | |         let _v = v;
335 | |     }
    | |_____^
    |
help: use the corresponding method
    |
333 |     for v in m.values_mut() {
    |         ^

error: you seem to want to iterate on a map's values
   --> $DIR/for_loop.rs:338:5
    |
338 | /     for (_, v) in &mut *m {
339 | |         let _v = v;
340 | |     }
    | |_____^
    |
help: use the corresponding method
    |
338 |     for v in (*m).values_mut() {
    |         ^

error: you seem to want to iterate on a map's keys
   --> $DIR/for_loop.rs:344:5
    |
344 | /     for (k, _value) in rm {
345 | |         let _k = k;
346 | |     }
    | |_____^
    |
help: use the corresponding method
    |
344 |     for k in rm.keys() {
    |         ^

error: aborting due to 50 previous errors